1. Field of the Invention
One or more embodiments of the present invention relate to a turn cancel signal output device for a vehicle which provides a trigger for cancelling the operating state of a direction indicator mounted on the vehicle based on the operation state of the steering wheel of the vehicle.
2. Description of the Related Art
For example, when a vehicle moves to adjacent another traveling lane on a road having plural traveling lanes (hereinafter, the changing of the traveling lanes of a vehicle will be called as lane change) or when a vehicle turns right or left at an intersection to change a course (hereinafter, the changing of the course of a vehicle to right or left will be called as turn), it is necessary to make a sign of direction indication so that drivers of other vehicles can recognize it.
In order to make such the sign of direction indication, a vehicle is provided with turn signal lamps as direction indicators (blinkers). Further, when a driver operates an operation lever provided near the steering wheel of a vehicle, the turn signal lamps disposed on the right side or the left side can be blinked.
In the case of the lane change, it is necessary to blink the turn signal lamps for several seconds before changing lanes so that drivers of other vehicles can recognize it. Further, in the case of the turn, it is necessary to maintain the blinking of the turn signal lamps until the completion of the turn.
In general vehicles, the operation lever for operating the direction indicators has operation positions of two stages. For example, when a driver applies a force to the operation lever to thereby slightly incline the lever (position of first stage), the turn signal lamps blink while the force is applied to thereby hold the lever at this stage. In other words, when the force applied in order to hold the lever is released, the lever restores to a predetermined neutral position due to a spring force and then the blinking operation of the turn signal lamps terminates.
On the other hand, when a driver applies a force to the operation lever to thereby largely incline the lever (position of second stage), the position of the lever is mechanically held. Thus, the turn signal lamps are maintained in the blinking state even when the force applied to the lever is released. Further, since a mechanism for mechanically detecting the steering state of the steering wheel is provided, the holding of the operation lever is automatically released when the steering operation is terminated.
Accordingly, in the usual driving, the position of the first stage of the operation lever is used in the case of the lane change, whilst the position of the second stage of the operation lever is used in the case of right turn or left turn. By using the position of the second stage, since it is not necessary to continuously apply a force for holding the operation lever during the driving operation of the right turn and left turn accompanying the rotating operation of the steering wheel, the driving operation can be facilitated. Further, when the right turn or the left turn terminates, the termination state thereof is mechanically detected and the operation lever automatically restores to the neutral position. Thus, a driver is not required to perform a particular operation for terminating the blinking of the turn signal lamps.
As such the device for controlling the blinking of turn signal lamps, there have been known electronic control devices each employing a sensor for detecting a steering angle, as disclosed in JP-A-2005-35343, JP-A-2011-88480, and JP-A-2011-131631, for example.
JP-A-2005-35343 discloses a technique in which a lever switch of an automatic restoration type and a steering angle sensor for detecting the rotational direction and the angle of a steering wheel are connected to control means, and the control means outputs a predetermined turn signal based on the operation signal of the lever switch. Further, JP-A-2005-35343 discloses a technique that turn signal lamps are blinked by the turn signal, the steering angle sensor detects the rotational position of the steering wheel, and the outputting of the turn signal is stopped to thereby turn-off the turn signal lamps in a straight travelling position.
JP-A-2011-88480 discloses a technique for automatically turning-off turn signal lamps at a more suitable timing at the time of changing traveling lanes. To be concrete, the turn signal lighting control device of JP-A-2011-88480 mounts a yaw rate sensor and a steering angle sensor. In a case where the initial speed is in a high speed range, this device determines a turning-off condition based on a yaw rate detection signal which is high in the reliability of the detection result in a high speed traveling. On the other hand, in a case where the initial speed is in a low speed range, this device determines the turning-off condition based on a steering angle detection signal which is high in the reliability of the detection result in a low speed traveling.
JP-A-2011-131631 discloses a technique for preventing the erroneous turning-off of turn signal lamps at the time of right turn and left turn. To be concrete, the turn signal lighting control device of JP-A-2011-131631 proposes the switching of a turning-off condition by automatically distinguishing the right/left turning and the traveling lane change based on whether or not the steering angle of a steering angle sensor reaches a cancel preparation angle.